Regulation of P2X7nucleotide receptor function in human monocytes by extracellular ions and receptor density

2001 ◽  
Vol 280 (4) ◽  
pp. C943-C953 ◽  
Author(s):  
Lalitha Gudipaty ◽  
Benjamin D. Humphreys ◽  
Gary Buell ◽  
George R. Dubyak
Keyword(s):  
Cell Surface ◽  
Human Blood ◽  
Pore Formation ◽  
Cell Types ◽  
Receptor Activation ◽  
Receptor Expression ◽  
Receptor Protein ◽  
Receptor Subtype ◽  
Mrna Levels ◽  
Blood Monocytes

P2X receptors function as ATP-gated cation channels. The P2X7receptor subtype is distinguished from other P2X family members by a very low affinity for extracellular ATP (millimolar EC50) and its ability to trigger induction of nonselective pores on repeated or prolonged stimulation. Previous studies have indicated that certain P2X7receptor-positive cell types, such as human blood monocytes and murine thymocytes, lack this pore-forming response. In the present study we compared pore formation in response to P2X7receptor activation in human blood monocytes with that in macrophages derived from these monocytes by in vitro tissue culture. ATP induced nonselective pores in macrophages but not in freshly isolated monocytes when both cell types were identically stimulated in standard NaCl-based salines. However, ion substitution studies revealed that replacement of extracellular Na+and Cl−with K+and nonhalide anions strongly facilitated ATP-dependent pore formation in monocytes. These ionic conditions also resulted in increased agonist affinity, such that 30–100 μM ATP was sufficient for activation of nonselective pores by P2X7receptors. Comparison of P2X7receptor expression in blood monocytes with that in macrophages indicated no differences in steady-state receptor mRNA levels but significant increases (up to 10-fold) in the amount of immunoreactive P2X7receptor protein at the cell surface of macrophages. Thus ability of ATP to activate nonselective pores in cells that natively express P2X7receptors can be modulated by receptor subunit density at the cell surface and ambient levels of extracellular Na+and Cl−. These mechanisms may prevent adventitious P2X7receptor activation in monocytes until these proinflammatory leukocytes migrate to extravascular sites of tissue damage.

Effect of chronic corticosterone treatment on expression and distribution of serotonin 5-HT7 receptors in rat adrenal glands

2019 ◽  
Vol 97 (10) ◽  
pp. 924-931 ◽  
Author(s):  
Neeshu Saroj ◽  
Shiv Shanker ◽  
Manuel A. Fernández-Parilla ◽  
Pedro López-Sánchez ◽  
José A. Terrón
Keyword(s):  
Adrenocorticotropic Hormone ◽  
Adrenal Glands ◽  
Receptor Activation ◽  
Receptor Expression ◽  
Receptor Protein ◽  
Control Group ◽  
Mrna Levels ◽  
Polymerase Chain ◽  
Corticosterone Treatment ◽  
Experimental Comparisons

Sensitized stress-induced corticosterone (CORT) secretion in chronically stressed rats involves 5-HT7 receptor activation. The effect of 14-day chronic CORT and vehicle (VEH) administration on 5-HT7 receptor expression in adrenal glands, adrenal 5-HT content, and adrenocorticotropic hormone and CORT secretion was analysed. On day 15, VEH- and CORT-treated animals were perfused or decapitated without stress exposure (0 min) or after 10 and 30 min of restraint for collection of trunk blood and tissues. 5-HT7 receptor-like immunoreactivity (5-HT7R-LI), 5-HT7 receptor protein, and mRNA levels were determined by immunohistochemistry, Western blot, and reverse transcription polymerase chain reaction assays, respectively; 5-HT levels and hormones were quantified using HPLC and ELISA kits, respectively. An undisturbed control group was included for most experimental comparisons. Chronic CORT strongly increased 5-HT7R-LI in the outer adrenal cortex, as well as 5-HT7 receptor protein and mRNA in whole adrenal glands; adrenal 5-HT content also increased in these animals. Decreased adrenocorticotropic hormone and CORT secretion at 30 min of restraint occurred in CORT-treated rats. The results support the notion that chronic stress-induced increase of adrenocortical 5-HT7 receptors and adrenal 5-HT content is a glucocorticoid-dependent phenomenon; the development of magnified stress-induced 5-HT7 receptor-mediated CORT responses in chronically stressed animals nevertheless likely involves additional mechanisms.

scholarly journals Pregnancy-enhanced Ca2+ responses to ATP in uterine artery endothelial cells is due to greater capacitative Ca2+ entry rather than altered receptor coupling

2006 ◽  
Vol 190 (2) ◽  
pp. 373-384 ◽  
Author(s):  
Shannon M Gifford ◽  
Fu-Xian Yi ◽  
Ian M Bird
Keyword(s):  
Endothelial Cells ◽  
Uterine Artery ◽  
Purinergic Receptor ◽  
Cell Types ◽  
P2y Receptors ◽  
Receptor Expression ◽  
Receptor Subtype ◽  
Initial Transient ◽  
Receptor Coupling ◽  
Specific Variation

Uterine artery endothelial cells (UAEC) derived from pregnant (P-UAEC) and nonpregnant (NP-UAEC) ewes retain pregnancy-specific differences in cell signaling as well as vasodilator production through passage 4. In particular, when P- and NP-UAEC are stimulated with ATP over a 2.5 min recording period, they exhibit similar initial transient peaks in the intracellular free Ca2+ concentration ([Ca2+]i), but the P-UAEC show a heightened sustained phase. In order to establish whether thiswas due to an altered subclass of purinergic receptor (P2), both the dose dependencyof [Ca2+]i responses to ADP and UTP and the profile of purinergic receptor expression are determined in NP- and P-UAEC. Our findings indicate that while several isoforms of P2X and P2Y receptors are present, it is P2Y2 that is responsible for the ATP-induced initial transient peak in both cell types. We also characterized several key components of the ATP-induced Ca2+ signaling cascade, including the inositol 1,4,5-trisphosphate receptor and G-proteins, but could not confirm any pregnancy-specific variation in the protein expression that correlated with pregnancy-specific differences in prolonged Ca2+ signaling. We thus investigated whether such a difference may be inherent to the cell itself rather than specific to the purinergic receptor-signaling pathway. Using thapsigargin (Tg), we were able to demonstrate that the initial Tg-sensitive intracellular pool of Ca2+is nearly identical with the capacity in both cell types, but the P-UAEC is nonetheless capable of greater capacitative Ca2+ entry (CCE) than NP-UAEC. Furthermore, CCE induced by Tg could be dramatically inhibited by 2-aminoethoxydiphenyl borate, suggesting a role for store-operated channels in the ATP-induced [Ca2+]i response. We conclude that changes at the level of capacitative entry mechanisms rather than switching of receptor subtype or coupling to phospholipase C underlies pregnancy adaptation of UAEC at the level of Ca2+signaling.

scholarly journals Regulation of interleukin 6 receptor expression in human monocytes and monocyte-derived macrophages. Comparison with the expression in human hepatocytes.

1989 ◽  
Vol 170 (5) ◽  
pp. 1537-1549 ◽  
Author(s):  
J Bauer ◽  
T M Bauer ◽  
T Kalb ◽  
T Taga ◽  
G Lengyel ◽  
...  
Keyword(s):  
Plasma Cells ◽  
Human Peripheral Blood ◽  
Receptor Expression ◽  
Mrna Levels ◽  
Blood Monocytes ◽  
Inflammatory Conditions ◽  
High Concentrations ◽  
Human Primary Hepatocytes ◽  
Stimulation Of

IL-6 is a cytokine with pleiotropic biological functions, including induction of the hepatic acute phase response and differentiation of activated B cells into Ig-secreting plasma cells. We found that human peripheral blood monocytes express the IL-6-R, which is undetectable on the large majority of lymphocytes of healthy individuals. Stimulation of monocytes by endotoxin or IL-1 causes a rapid downregulation of IL-6-R mRNA levels and a concomitant enhancement of IL-6 mRNA expression. IL-6 itself was found to suppress the IL-6-R at high concentrations. A gradual decrease of IL-6-R mRNA levels was observed along in vitro maturation of monocytes into macrophages. We show that downregulation of IL-6-R mRNA levels by IL-1 and IL-6 is monocyte specific, since IL-6-R expression is stimulated by both IL-1 and IL-6 in cultured human primary hepatocytes. Our data indicate that under noninflammatory conditions, monocytes may play a role in binding of trace amounts of circulating IL-6. Repression of monocytic IL-6-R and stimulation of hepatocytic IL-6-R synthesis may represent a shift of the IL-6 tissue targets under inflammatory conditions.

scholarly journals Regulation of the Endothelin/Endothelin Receptor System by Interleukin-1β in Human Myometrial Cells

Endocrinology ◽  
2005 ◽  
Vol 146 (11) ◽  
pp. 4878-4886 ◽  
Author(s):  
Michelle Breuiller-Fouché ◽  
Catherine Morinière ◽  
Emmanuelle Dallot ◽  
Stéphanie Oger ◽  
Régis Rebourcet ◽  
...  
Keyword(s):  
Prolonged Exposure ◽  
Receptor Expression ◽  
Receptor Subtype ◽  
Mrna Levels ◽  
Receptor System ◽  
Myometrial Cell ◽  
Myometrial Cells ◽  
Uterine Contractions ◽  
Eta Receptor ◽  
Etb Receptor

Proinflammatory cytokines produced at the fetomaternal interface, such as IL-1β, have been implicated in preterm and term labor. The present study was performed to evaluate the influence of IL-1β on the endothelin (ET)/ET receptor system in human myometrial cells. We report that myometrial cells under basal conditions not only respond to but also secrete ET-1, one of the main regulators of uterine contractions. Prolonged exposure of the cells to IL-1β led to a decrease in prepro-ET-1 and ET-3 mRNA correlated with a decrease in immunoreactive ET-1 and ET-3 levels in the culture medium. Whereas ETA receptor expression at both protein and mRNA levels was not affected by IL-1β treatment, we demonstrated an unexpected predominance of the ETB receptor subtype under this inflammatory condition. Whereas the physiological function of ETB remains unclear, we confirmed that only ETA receptors mediate ET-1-induced myometrial cell contractions under basal conditions. By contrast, prolonged exposure of the cells to IL-1β abolished the contractile effect induced by ET-1. Such a regulation of IL-1β on the ET release and the balance of ETA to ETB receptors leading to a loss of ET-1-induced myometrial cell contractions suggest that complex regulatory mechanisms take place to constraint the onset of infection-induced premature contractions.

scholarly journals β-blockers Reverse Agonist-Induced β2-AR Downregulation Regardless of Their Signaling Profile

2020 ◽  
Vol 21 (2) ◽  
pp. 512
Author(s):  
Sonia Maccari ◽  
Vanessa Vezzi ◽  
Federica Barbagallo ◽  
Tonino Stati ◽  
Barbara Ascione ◽  
...  
Keyword(s):  
Cell Surface ◽  
Human Lymphocytes ◽  
Cell Types ◽  
Hek293 Cells ◽  
Enzyme Linked Immunosorbent Assay ◽  
Mrna Levels ◽  
Receptor Density ◽  
Biased Agonism ◽  
Β Blocker ◽  
Β Blockers

Altered β-adrenergic receptor (β-AR) density has been reported in cells, animals, and humans receiving β-blocker treatment. In some cases, β-AR density is upregulated, but in others, it is unaffected or even reduced. Collectively, these results would imply that changes in β-AR density and β-blockade are not related. However, it has still not been clarified whether the effects of β-blockers on receptor density are related to their ability to activate different β-AR signaling pathways. To this aim, five clinically relevant β-blockers endowed with inverse, partial or biased agonism at the β2-AR were evaluated for their effects on β2-AR density in both human embryonic kidney 293 (HEK293) cells expressing exogenous FLAG-tagged human β2-ARs and human lymphocytes expressing endogenous β2-ARs. Cell surface β2-AR density was measured by enzyme-linked immunosorbent assay (ELISA) and flow cytometry. Treatment with propranolol, carvedilol, pindolol, sotalol, or timolol did not induce any significant change in surface β2-AR density in both HEK293 cells and human lymphocytes. On the contrary, treatment with the β-AR agonist isoproterenol reduced the number of cell surface β2-ARs in the tested cell types without affecting β2-AR-mRNA levels. Isoproterenol-induced effects on receptor density were completely antagonized by β-blocker treatment. In conclusion, the agonistic activity of β-blockers does not exert an important effect on short-term regulation of β2-AR density.

Temporal decrease in renal sensory responses in rats after chronic ligation of the bile duct

2002 ◽  
Vol 283 (1) ◽  
pp. F164-F172 ◽  
Author(s):  
Ming-Chieh Ma ◽  
Ho-Shiang Huang ◽  
Chiang-Ting Chien ◽  
Ming-Shiou Wu ◽  
Chau-Fong Chen
Keyword(s):  
Bile Duct ◽  
Receptor Activation ◽  
Receptor Protein ◽  
Sensory Receptor ◽  
Mrna Levels ◽  
Sensory Receptors ◽  
Common Bile Duct Ligation ◽  
Renal Nerve ◽  
Duct Ligation ◽  
Sensory Responses

Renal responses to renal sensory receptor activation were examined in rats after 1 and 4 wk of common bile duct ligation (CBDL). Compared with sham-operated rats (Sham), urine and sodium excretion after acute saline loading was significantly reduced at both times after CBDL. The blunted excretory responses in CBDL rats, accompanied by less activation of afferent renal nerve activity (ARNA), were already apparent at 1 wk and became severe at 4 wk. The defect in ARNA activation in CBDL rats was further studied using specific stimuli to activate renal sensory receptors. Graded increases in intrapelvic pressure or renal pelvic perfusion of substance P (SP) elicited an increase in ARNA in Sham rats, these responses being temporally attenuated in CBDL rats. Despite no significant change in renal pelvic SP release, no renorenal reflex was demonstrable in 4-wk CBDL rats. Immunoblotting showed that expression of renal pelvic neurokinin 1 (NK-1) receptors was 32 and 47% lower in 1- and 4-wk CBDL rats, respectively, than in Sham rats, this decrease correlating well with plasma SP levels. The quantitative real-time RT-PCR showed similar levels of NK-1 receptor mRNA in the renal pelvis in the Sham and 4-wk CBDL groups. We conclude that impairment of renal excretory and sensory responses increases with the duration of cirrhosis. An impaired renorenal reflex in cirrhotic rats is involved in the defective activation of the renal sensory receptors could be due, in part, to the low expression of NK-1 receptors, which is dependent on the duration of CBDL. The decrease in NK-1 receptor protein levels is not due to a decrease in mRNA levels.

scholarly journals N-formylmethionyl-leucyl-[3H]phenylalanine binding, superoxide release, and chemotactic responses of human blood monocytes that repopulate the circulation during leukapheresis

Blood ◽  
1983 ◽  
Vol 62 (4) ◽  
pp. 918-923 ◽  
Author(s):  
E Alteri ◽  
EJ Leonard
Keyword(s):  
Human Blood ◽  
Binding Sites ◽  
Human Subjects ◽  
Peptide Binding ◽  
Transient State ◽  
Receptor Expression ◽  
Blood Monocytes ◽  
Superoxide Generation ◽  
Superoxide Release ◽  
Binding Curves

Abstract Human blood monocytes comprise two subpopulations: one migrates to the chemoattractant, N-formylmethionyl-leucyl-phenylalanine (fMet-Leu-Phe), and has saturable binding sites for this peptide; the other does not migrate and exhibits little peptide binding. To determine if expression of binding sites was a function of monocyte maturation, we depleted human subjects of blood monocytes by leukapheresis so that the circulation was repopulated by monocytes released from the bone marrow. Pre- and postleukapheresis monocytes were then compared for fMet-Leu- [3H]Phe binding, superoxide generation, and chemotactic responses. No significant differences in peptide binding curves were found, suggesting that receptor expression was stable over the maturational span represented by these two groups of cells. This supports the hypothesis that there are two distinct lineages of monocytes with respect to expression of receptors for fMet-Leu-Phe. An additional finding of interest was that the number of chemotactically responsive cells immediately postleukapheresis was half the control. This was a transient state; monocyte responses were normal 3 hr after termination of leukapheresis, suggesting that they rapidly become functionally mature.

scholarly journals Expression of LAIR-1 (CD305) on Human Blood Monocytes as a Marker of Hepatic Cirrhosis Progression

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
María Martínez-Esparza ◽  
Antonio José Ruiz-Alcaraz ◽  
Violeta Carmona-Martínez ◽  
María Dolores Fernández-Fernández ◽  
Gonzalo Antón ◽  
...  
Keyword(s):  
Liver Cirrhosis ◽  
Cell Surface ◽  
Human Blood ◽  
Total Content ◽  
Cell Surface Expression ◽  
Human Macrophage ◽  
Blood Monocytes ◽  
Cirrhotic Patients

Background and Aim. The presumed role of the inhibitory receptor LAIR-1 (CD305) in the inflammatory response suggests that it might contribute to the pathophysiology of chronic inflammatory diseases such as liver cirrhosis. We studied the LAIR-1 expression on liver macrophages and blood monocytes related to the progression of liver cirrhosis. Methods. The expression of LAIR-1 was analyzed by immunohistochemistry, flow cytometry, and Western blot. Results. We found a decreased number of macrophages expressing LAIR-1 in cirrhotic liver that could be due to a high presence of collagen, ligand of LAIR-1, in the fibrotic tissue which could downregulate its expression or interfere with the immunostaining. The expression of LAIR-1 decreased after cell differentiation, and the total content, but not the cell surface expression, increased after activation in the HL-60 human macrophage in vitro model. Blood monocytes exhibited higher LAIR-1 expression levels in cirrhotic patients, which were evident even in early clinical stages in all monocyte subsets, and greater in the “intermediate” inflammatory monocyte subpopulation. The in vitro activation of human blood monocytes did not increase its expression on the cell surface suggesting that the in vivo increase of LAIR-1 must be the result of a specific combination of stimuli present in cirrhotic patients. This represents an exclusive feature of liver cirrhosis, since blood monocytes from other chronic inflammatory pathologies showed similar or lower LAIR-1 levels compared with those of healthy controls. Conclusions. These results may indicate that monocyte LAIR-1 expression is a new biomarker to early detect liver damage caused by chronic inflammation in liver cirrhosis.

scholarly journals Repression of platelet-derived growth factor beta-receptor expression by mitogenic growth factors and transforming oncogenes in murine 3T3 fibroblasts.

1995 ◽  
Vol 15 (3) ◽  
pp. 1244-1253 ◽  
Author(s):  
C Vaziri ◽  
D V Faller
Keyword(s):  
Growth Factors ◽  
Growth Factor ◽  
Cell Surface ◽  
Growth Arrest ◽  
Serum Deprivation ◽  
Receptor Expression ◽  
Platelet Derived Growth Factor ◽  
Mrna Levels ◽  
Beta Receptor ◽  
3T3 Fibroblasts

Platelet-derived growth factor BB (PDGF-BB) is an important extracellular factor for regulating the G0-S phase transition of murine BALB/c-3T3 fibroblasts. We have investigated the expression of the PDGF beta receptor (PDGF beta R) in these cells. We show that the state of growth arrest in G0, resulting from serum deprivation, is associated with increased expression of the PDGF beta R. When the growth-arrested fibroblasts are stimulated to reenter the cell cycle by the mitogenic action of serum or certain specific combinations of growth factors, PDGF beta R mRNA levels and cell surface PDGF-BB-binding sites are markedly downregualted. Oncogene-transformed 3T3 cell lines, which fail to undergo growth arrest following prolonged serum deprivation, express constitutively low levels of the PDGF beta R mRNA and possess greatly reduced numbers of cell surface PDGF receptors, as determined by PDGF-BB binding and Western blotting (immunoblotting). Nuclear runoff assays indicate the mechanism of repression of PDGF beta R expression to be, at least in large part, transcriptional. These data indicate that expression of the PDGF beta R is regulated in a growth state-dependent manner in fibroblasts and suggest that this may provide a means by which cells can modulate their responsiveness to the actions of PDGF.

scholarly journals Expression and T cell Regulatory Action of the PD-1 Immune Checkpoint in the Ovary and Fallopian Tube

2020 ◽  
Author(s):  
Joshua Johnson ◽  
Peter Ka Sam ◽  
Rengasamy Asokan ◽  
Evelyn Llerena Cari ◽  
Elise S. Bales ◽  
...  
Keyword(s):  
T Cell ◽  
Tumor Cells ◽  
Fallopian Tube ◽  
Cell Types ◽  
Receptor Activation ◽  
Receptor Expression ◽  
Human Follicular Fluid ◽  
Checkpoint Signaling ◽  
Ligand Expression ◽  
Immunomodulatory Action

The Programmed Cell Death Protein-1 (PD-1/PDCD-1/CD279) checkpoint has powerful immunomodulatory action, including in the context of cancer. PD-1 receptor activation by its ligands (PD-L1/2) is associated with downregulated immune response, and tumor cells can avoid surveillance via PD-1 and/or ligand expression. While receptor expression is largely limited to lymphoid, myeloid, and tumor cells, we show that membrane bound and soluble variants of PD-1 and ligands are also expressed by permanent constituent cell types of the human ovary and fallopian tube, including granulosa cells and oocytes. PD-1 and soluble ligands were highly enriched in exosome fractions in human follicular fluid at bioactive levels that can control T cell PD-1 activation. PD-1 checkpoint signaling may be involved in physiological ovarian functions including follicle, and ultimately, germline and embryo immune-privilege.

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